Portable devices such as tablets, smart phones, and smart watches have become popular recently due to the rapid advancement in low-cost semiconductor technologies. Portable devices as well as other electronic devices may incorporate antenna elements for radio frequency (RF) communication as well as for radar applications such as object ranging, tracking, and identification. In some applications, multiple antenna elements may be utilized for beamforming, transmit diversity and multiple input, multiple output (MIMO) configurations, and also as radar sensors that can detect user motions (known as gesture sensors).
As portable devices become smaller and device functionality is expanded, it may be difficult to fit additional antennas within the device casing while still provided desired functionality. For example, many applications of radar functionality may be useful in the region in front of the display screen of a tablet, smart phone, smart watch, or other electronic device. However, signals sent and received by a radar system may not be able to penetrate the display screen of the device. Therefore, portable devices which incorporate a radar system that is capable of operating in the region in front of a display screen of the portable device may be desirable.